Multi-source Time Series of Canopy Chlorophyll for Crops – Corn and Soybean Rotation

Monitoring canopy chlorophyll content (CCab) is essential for assessing crop photosynthetic function and productivity, yet characterizing its temporal variability remains a major challenge. This study aimed to generate a consistent, high-temporal-resolution CCab time series across seasons, crop types (corn and soybean), and years (2015–2024) by integrating in situ measurements with multispectral satellite imagery. CCab was derived using field data (leaf chlorophyll, leaf area index, and canopy reflectance) directly and as inputs to the Soil Canopy Observation Photosynthesis Energy (SCOPE) model. We produced dense CCab time series by combining field data with red-edge indices (CI705) from Harmonized Landsat/Sentinel (HLS) and Planet SuperDove (PSD) constellations. HLS CI705 was strongly correlated with PSD CI705 but outperformed it, yielding more consistent CCab estimates with lower uncertainty. Multi-sensor fusion using harmonized red-edge indices successfully captured fine-scale seasonal dynamics previously unattainable by a single sensor, and confirmed the transferability of CCab across crop types, seasons and multiple years. While promising for operational monitoring, the study highlights the critical need for continued advancements in cross-sensor calibration, radiometric harmonization and careful trending and comparison of multi-source red-edge indices and CCab product.